Fungi of Great Britain and Ireland: Thallus crustose, epilithic, placodioid, tightly attached to the substratum, forming ± well-delimited rosettes, often confluent and difficult to distinguish, very variable in diameter, salmon pigmented due to a strongly developed white pruina, which can leave the center of the thallus virtually white, K+ purple. Areoles 0.3-1.3 mm in diam., flat to convex, formed from lobe fragmentation, irregularly polygonal. Marginal lobes 0.3-1.5 (-1.7) mm long and 0.2-1.2 mm wide at the tips, convex, becoming flat toward the apex, where they usually broaden, finger-like or strongly branched, always contiguous and imbricate. Upper cortex 15-65 (-85) μm thick, with an orange pigmented outer layer 6-20 (-25) μm thick and a hyaline inner layer 8-45 (-60) μm thick, with isodiametric to elongate cells. Algal layer ± continuous, occasionally grouping, 40-125 (-160) μm thick. Soredia and isidia absent. Photobiont chlorococcoid, with globose cells, 6.5-22 (-24) μm in diam. Medulla quite lax, with hyphae 2.5-5 (-6.5) μm diam. Anamorph: no information available. Teleomorph: ascomata apothecia, abundant, densely grouped, 0.2-1.2 mm diam., rounded, often deformed by mutual compression, usually located on areoles and lobe bases, emergent and, occasionally basally constricted. Disk flat to strongly convex, orange, brownish or dark red, slightly pruinose, K+ purple. Margin 30-130 μm wide, same colour as the disk. Epithecium (6-) 8-10 (-12) μm thick, orange, K+ purple. Hymenium 50-80 (-95) μm tall, hyaline. Subhymenium and hypothecium hyaline. Interascal tissue of paraphyses, (1.5-) 2-3 (-3.5) μm, septate, sometimes branched near the apex, with one or two swollen apical cells, (2.5-) 3-7 (-8.5) μm diam. Asci (40-) 45-62 (-65) x 9-16.5 (-18.5) μm, clavate, 8-spored. Ascospores (9-) 10.5-13.5 (-15.5) x (4.5- ) 5.5-7 (-8.5) μm, broadly ellipsoidal, polarilocular, hyaline, with an equatorial thickening (‘septum’) (2.5-) 3-4.5 (-6) μm in length, length/width ratio (1.2-) 1.6-2.2 (-2.7) and length/equatorial thickening ratio (2.1-) 2.6-3.7 (-4.6).